Stabilization of crops



Patented June 10, 1952 STABILIZATION OF CROPS Joseph A. Chenicek,Bensenville, and William K. T. .Gleim, Orland Park, Ill., assignors .to

; Universal Oil Products Company, Chicago, Ill.,'

a corporation ofDelaware No Drawing. Application November 13, 1950,Serial No. 195,478

160laims. (01. 99-8) This application is a continuation-in-part Ofourcopendlng application Serial No. 732,142, filed March 3, 1947, nowPatent 'No.'2,535,058, issued December 26, 1950 and relates to thestabilization of crops and more particularly to a novel method "ofpreserving the desirable qualities thereof.

It 'has been found that the drying of crops either in the field or indrying equipment results in a loss-of valuable food accessory factors.For example, alfalfa looses anywhere from 45% to 85% of its carotenevalue during the drying treatment. Similarly, carotene is found in sweetpotatoes and in other yellow pigmented plants. Vitamin B1 (thiaminehydrochloride) is found in various seeds,-grains, nuts, legumes, fruitsand vegetables, while vitamin B2 (riboflavin) is found in wheat germ andleafy vegetables. Nicotinic acid (Niacm) is found in wheat germ and inseveral green leafy vegetables, while vitamin B6 (pyridoxine) is foundin whole grain cereals, crude cane molasses, etc. Vitamin-C (ascorbicacid) is found in citrus fruits, tomatoes, green peppers and variousother fresh fruits and vegetables, and vitamin E is found in wheat germoil, cotton seed oil, green leafy vegetables'and various grains. VitaminK1 is found in alfalfa, spinach, and other green vegetables.Pa-ntothenic acid is found in crude cane molasses and wheat germ.Several postulated vitamins which have not as yet been completelyaccepted, such as citrin, gizzard ero- -sion factor, etc., are found invarious crops, the

,tzitrin being present in citrus foods, and the giz- 'zard erosionfactor being present in alfalfa, kale, etc. It is understood that theabove is merely a brief reference to the vitamin content of variouscrops-and that these and other crops also may contain other vitamins as,for example, spinach contains vitamins A, B2 later knownas vitamin G(riboflavin) and C, beets contain vitamin B1, potatoes contain vitaminB2, parsley, cabbage, and berries contain vitamin C, etc.

In addition to vitamins or in absence of vitamins, various crops containother desirable substances which tend to deteriorate due to oxidativedeterioration. For example, various fatty acids, such as caprylic,.capric, lauric, myristic, almitic, stearic, oleic, linoleic, etc., arefound in the oils of coconut, babassu, palm kernel, olive, castor,peanut, rapeseed, cotton seed, corn, soy bean, etc. Alcohols are foundin cockfoot grass, wheat lucerne "leaf, etc. Various sterols are foundin plant oils, ergosterol, forexample, being found in soya bean oil.Further, crops may become rancid and lose desirable qualities'such astaste, odor,

retention of physical shape (non-wiltingiyetc, due to oxidativedeterioration.

The present invention offers a novel method of preventing or retardingthe oxidative deterioration of these substances in storage and duringmanufacture.

In one embodiment the present invention relates to a process forstabilizing crops subject to oxidative deterioration which comprisesadding thereto an inhibitor comprising a 5-hydroxy coumaran.

In a specificembodiment the present invention relates tothestabilizationof carotene containing crops subject to oxidativedeterioration which comprises applying thereto an inhibitor comprising a.5-hydroxy coumaran substituted .in the 6-position by a hydrocarbongroup of at least 3 carbon atoms.

In a more specific embodiment the present invention relates to thestabilization of alfalfa which comprises spraying alfalfa with aninhibitor comprising 2,2-dimethyl-6-tertiary butyl-5- hydroxy coumaran.

The term crops as used in the presentinvention is intended to includeany substance grown from the soil to be used as food for humans oranimals, either in the form as gatheredfrom the field or after suitablemodification in form. .such as by pressing, grinding, pulverizing,slurrying,

making into paste, flour, etc.; either used as such or after suitablecooking. Thus the present invention is applicable to the treatment offorage crops, such as alfalfa, clover, hay, fodder, e.tc.; grains suchas corn, wheat, oats,rice,-barley, .rye, soy beans, etc.; vegetablessuch as carrots, peas, spinach, beets, potatoes, parsley, cabbage,etc.-;fruits including both small fruitsand those grown on trees, such asberries, oranges, lemons, grapefruit, apples, bananas, melons, dates,figs, -etc.;

nut crops including peanuts, wa1nuts,-pecans,-almonds, chestnuts, hazelnuts, etc.; hops, coffee, tea, sugar, t-obacco,-etc. It is understoodthat the above crops are merely typical representatives and that thebroad scope of the present invention is not intended to be undulylimited to the crops specifically mentioned but is to include all othercrops subject to oxidative deterioration.

When the inhibitor is sprayed on the crops in the field, it ispreferable to utilize an inhibitor which is not water soluble so thatthe inhibitor will not be washed away by the rain. The .inhibitors ofthe present inventionare not water soluble and therefore areparticularly suitable for this purpose. In addition, theseinhibitors'are .wax soluble and therefore willzpenetr'ate through 3 thewaxy coating of various crops and will enter into the cells of the cropsto effect stabilization thereof.

It will be noted that the inhibitors of the present invention areparticularly advantageous for use in the stabilization of cropscontaining carotene and that these inhibitors serve to prevent loss ofcarotene from the crops and thereby to retain this desirable property.How--' ever, it is understood that the inhibitors also.

serve to retain other desirable properties in the crops as hereinbeforeset forth.

2,2 dimethyl G-tertiary -.'butyl-5'-hydroxy-cou maran. The final productwas recovered after water washing, extraction with ether, water washing,drying, evaporation and recrystallization from alcohol or benzene.

2-methyl-5-hydroxy-coumaran was prepared I by first forming the. allylether of 4-methoxy- In a broad embodiment the inhibitor of the presentinvention comprises a 5-hydroxy coumaran. Preferably the 5-hydroxycoumaran is of the In the chemical structure shown above, B may behydrogen but preferably is a hydrocarbon radical containing at least 3carbon atoms, R RR, R and R may be hydrogen, alkyl, aryl, aralkyl,alkaryl, cyclohexyl, etc. and these substituentsmay themselves besubstitutedby hy- "droxyor. amino groups. 7 ,The inhibitors of thepresent invention may be prepared in any suitable manner. A preferredmethod of preparing the substituted hydroxy-coumarans comprises reactinghydro quinone with methallyl chloride in the presence of .asuitable saltof a strong base and a weak acid, such as potassium carbonate, to formthe corresponding mono-methallyl-ether of hydroquinone. Themono-methallyl-ether of hydroquinone is then rearranged by means of heatto form 2-methallyl-hydroquinone, which is then refluxed in the presenceof a suitable acid, such j as formic acid, to form 2,2-dimethy1-5-hydroxy coumaran. The hydrocarbon substituent group isadded in the6-position by alkylating with an alcohol of the desired olefin in thepresence of a suitable catalyst, such as phosphoric acid. In place ofmethallyl chloride, methallyl bromide may be used and, in place of thealcohol for alkylation, the olefin or other olefin-producing substancemay be employed. The following examples show the preparation of specificcompounds in detail.

' 2,2 dimethyl 6 tertiary butyl 5 hydroxy-coumaran was prepared asfollows: 1 mol of hydroquinone, 1.2 mols of methallyl chloride, 0.51 molof potassium carbonate and 200 cc. of water were refluxed, whilestirring for 48 hours, working in a nitrogen atmosphere being optional.The water layer which was clear and colorless was drawn oil anddiscarded. The hydroquinone methallyl ether-methallyl chloride mixturewas dissolved in one liter of ethyl ether and the ether solution waswashed, dried and evaporated. One hundred and forty grams of productwere obtained which amounts to a yield of 85% based on'the hydroquinone.The product was heated slowly to 250 C. and, after cooling,'was refluxedin an equal weight of 88% formic'acid for 10 hours at 110 C., afterwhich phenoljwith allyl bromide in the presence of potassium carbonateand acetone. The compoundwas rearranged by means of heat to the 2-allyl-4-methoxyphenol which in turn was transformed into 2-methyl-5-hydroxycoumaran by refluxing in glacial acetic acid and hydrogen bromide.

Preferred inhibitors of the present invention comprise 6-butyl-5-hydroxycoumarans including .2 '-"methyl -6-' tertiary-lo1'1tyl-'iiehydroxy-coumara'n, 2,2 dimethy1 '6-tertiary-butyl-5-hydroxy coumaran, 2 methyl6-"secondary-butyl-5-hydroxy-coumaran, 2,2 dimethyl 6secondarybutyl-5-hydroxy-coumaran, 2-methyl-6-isobutyl- 5 hydroxycoumara'n, 2,2-dimethyl-6-tertia'rybutyl-5-hydroxy-coumaran, etc; aswell as other branched chain'substituted compounds including 2methyl-6-isopropyl-5-hydroxy-coumaran, 2,2 dimethyl 6 isopropyl 5hydroxy coumaran,- 2 methyl 6 tertiary-amyl-5rhydroxycoumaran,2,2-dimethyl 6 tertiary-amyl-5-hydroxy-coumaran, etc. Other satisfactoryinhibitors include those in which the 'alkylsubstituent in the6-position comprises a radical selected from n-propyl, n-butyl, n-amyl,etc.

It is understood that; the various inhibitors which may be prepared andused within the broad scope of the present inventionare not neces'esarily equivalent in their activity but that they all will serve tostabilize the crops in some de= gree, 4 The inhibitor is'sprayed ordusted 'on the crops either before or after cutting. When desired, theinhibitor may be dissolved in a suitable non-toxic organic solvent oremulsified with a suitable wetting agent. As these inhibitors aresoluble'in most organic solvents, the particular solvent to be used in agiven instance will depend primarily upon the effect the solvent mayhave on the crops and secondarily on the cost thereof; -A lighthydrocarbon naphtha or kerosene which is volatile and thus willevaporate to leave themhi'bitor absorbed .in the crops may be employed,7

although alcohols, glycerine, g-lycols, ethers, aldehydes, ketones, etc.which meet the desired requirements may be used. Propylene glycol is apreferred solvent for this purpose. When utilized as an emulsion, theinhibitor'may be com mingled with a wetting agent such as Aerosol,Nacconol, Santomerse, etc. or thoseof the gardino] type and, in fact,with any suitable non-toxic wetting agent. In still another embodimentthe inhibitor may be emulsified with water and then used as a spray ormade in a solution with the various solvents hereinbefore set forth andthen emulsifiedwith the wetting'agent, with or with out a solutizingagent, and utilized as such or in a solution or emulsion with water.For'dusting, the inhibitor or a solution or emulsion thereof ashereinbefore set forth may be admixed with'suitable inert material, suchas clays. a

The inhibitor may be sprayed or dusted by hand or from aeroplanes or byany other suit- .butyl-'-hydroxy coumaran was able method in orderto'distribute the inhibitor in finely divided particles'over the crops.either ities not only of the eaves themselves, butal Q the oilsand'thelike obtained from the crops. Similarly, "the "inhibitor willpenetrate into the larger produce such as oranges, lemons, melons,apples, pears, etc., and thereby will serve to preserve the vitamincontent and other desirable properties thereof.

The inhibitors may be sprayed or dusted alone or in combination withinsect or weed killing materials. In some cases, the insect or weedkilling material may serve as a solvent for the inhibitor as, forexample, when it is desired to use a hydrocarbon fraction, such askerosene, for this purpose. It is understood that the inhibitor may beused in conjunction with inhibitor activators or synergists, such asphosphoric acid, ascorbic acid, citric acid, esters of these acids, etc.It is also understood that these inhibitors may be used along with otherinhibitors such as propyl gallate, NDGA (nordihydroguaiaretic acid),lauryl thio-dipropionate, thio-dipropionic acid, Z-tertiarybutyl-4-methoxyphenol, etc.

It is understood that the spraying or dusting of the crops may be donewhile the crops are in the field, either prior to or after cutting, orthat the inhibitor may be applied after the crops have been gathered andstored. The amount of inhibitor to be applied to the crops may varyconsiderably, but in general will range from about 0.0001% to about 0.1%by weight of active ingredient.

The following example is introduced to illustrate further the noveltyand utility of the present invention but not with the intention ofunduly limiting the same.

Example I This run was made by charging 100 grams of alfalfa into a onegallon rotating drum to which 0.02% byweight of 2,2-dimethyl-6-tertiarysprayed by means of a spray gun. The inhibitor was prepared in themanner hereinbefore set forth and was further prepared as a solution in100 ml. of acetone. In order to prevent wetting of the alfalfa by theacetone the run was made in the presence of air introduced at a rate ofabout ml. per minute. The carotene determinations were made according tothe method described in Analytical Chemistry 19, No. 3, 170 (1947).

The alfalfa had an original content of 285 parts per million ofcarotene. The alfalfa was divided into different samples and the sampleswere stored at 100 F. Analyses were made after 4, 8 and 60 days. Theresults of these analyses are given in the following table.

Table I Carotene Content, parts per gram, after- From the above data itwill be noted that the carotene content of the alfalfa dropped from 285-6 to -parts per millionin 60 days. 6n the other hand, the-'-alfalfa--inhibited with"-2,-2-;dimeth'yle6.-

tertiary butyl-5-hydroxy'"coumaran dropped "to only ,130'parts permillion after 60 day thus representing 2.13% greater carotene "contentover the non-inhibitedalfalfa. The particular alfalfa used inthisexample' had been 'stor'ed'for some time before the --runs reportedabove were made.

It 'is preferred that the inhibitor be added to the alfalfa promptlyafter 'cuttingand; in sueh'cases, the beneficial cfiectsobtained by theuseof the inhibitor will "be even greater and thus will serve toinhibitto a considerable extent the loss of carote'nein the alfalfa,

We claim as our invention:

1. A process for stabilizing crops subject to oxidative deteriorationwhich comprises applying thereto an inhibitor comprising afi-hydroxycoumaran substituted in the 6-position by a branched chainalkyl group.

2. A process for stabilizing crops subject to oxidative deteriorationwhich comprises applying thereto an inhibitor comprising a5-hydroxycoumaran substituted in the 6-position by a hydrocarbon groupof at least 3 carbon atoms.

3. A process for stabilizing crops subject to oxidative deteriorationwhich comprises applying thereto an inhibitor comprising a6-butyl-5-hydroxy-coumaran.

4. A process for stabilizing crops subject to oxidative deteriorationwhich comprises applying thereto an inhibitor comprising 2,2-dimethyl-6-tertiary butyl-5-hydroxy-coumaran.

5. A process for stabilizing carotene-contain ing crops subject tooxidative deterioration which comprises distributing over the cropsfinely divided particles of an inhibitor comprising a 5-hydroxy-coumaran substituted in the 6-position by a hydrocarbon group ofat least 3 carbon atoms.

6. A process for stabilizing carotene-containing crops subject tooxidative deterioration which comprises distributing over the crops aninhibitor comprising 2 methyl-fi-tertiary-butyl- 5-hydroxy-coumaran. v

'7. A process for stabilizing carotene-containing crops subject tooxidative deterioration which comprises distributing over the crops aninhibitor comprising 2,2-dimethyl-S-tertiary-butyl-5- hydroxy-coumaran.

8. A process for stabilizing alfalfa to prevent loss in carotene whichcomprises spraying the alfalfa with an inhibitor comprising a5-hydroxycoumaran substituted in the 6-position by a hydrocarbon groupof at least 3 carbon atoms.

9. A process for stabilizing alfalfa to prevent loss in carotene whichcomprises spraying the alfalfa with an inhibitor comprising a 6-butyl-5-hydroxy-coumaran.

10. A process for stabilizing alfalfa to prevent loss in carotene whichcomprises spraying the alfalfa with an inhibitor comprising2,2-dimethyl-6-tertiary-butyl-5-hydroxy-coumaran.

11. A process for stabilizing alfalfa to prevent loss in carotene whichcomprises spraying the alfalfa with an inhibitor comprising 2-methyl-6-tertiary-butyl-5-hydroxy-coumaran.

12. Crops normally subject to oxidative deterioration and containing asan inhibitor against such deterioration a 5-hydroxy-coumaran substitutedin the 6-position by a branched chain alkyl group.

13. Crops normally subject to oxidative deterioration and containing asan inhibitor against 7 such deterioration a, 5-'hydroxycoumaran subrREFERENCES CITED 'stltuted inwhe' e'vposmon by a hydrocarbon Thefollowing references are of record in the group of at 1east3 carbonatoms. 2 file 'of this patent:

6-buty1-5-hydroxy-coumaran. Number Name 2 Date 4 w 15. Alfalfacontaining, as an inhibitor against 2,320,746 Paul June 1, 1943 Voxidative deterioration of its carotene content, 2,421,812 Smith et a1June 10, 1947 2-methyl-6 tertiary butyl 5 hydroxy cou- 2,513,002Chenicek June 27, 1950 maran. 10 x i 16. Alfalfa containing, as aninhibitor against 'oxidative deterioration of its carotene content,

14. Alfalfa containing, as an inhibitor against oxidative deteriorationof its carotene content, a 5 UNITED STATES PATENTS2,2-dimethyl-6-tertiary-buty1-5 hydroxy coumaran. V JOSEPH A.CI-IENICEK. 15

: WILLIAM K. T. GLEINI.

1. A PROCESS FOR STABILIZING CROPS SUBJECT TO OXIDATIVE DETERIORATIONWHICH COMPRISES APPLYING THERETO AN INHIBITOR COMPRISING A5-HYDROXYCOUMARAN SUBSTITUTED IN THE 6-POSITION BY A BRANCHED CHAINALKYL GROUP.